#!/usr/bin/env python
# @FileName :1.12jibenshurushuchu.py
# @Time :2024/1/14 11:44
# @Author :mingshui

u_input = input("请输入一串字符：")
count = 0

for zifu in u_input:
    if zifu == 'a':
        count += 1
print("字符'a'出现的次数为：", count)
